This invention relates generally to self-propelled devices for cleaning submerged surfaces. More particularly, it relates to a swimming pool cleaning device incorporating a flow control valve for establishing intermittent flow of a fluid through the cleaner and a rotating mechanism to assist the cleaner to steer away from obstructions and avoid repetitive patterns of travel across the surface to be cleaned.
Mechanical pool cleaners which utilize the flow of water drawn through the cleaner by means of a connectable flexible suction pipe in communication with a filtration system pump are well known. Such pool cleaners are termed suction cleaners. Some suction cleaners interrupt the flow of the water induced through at least one passage through the cleaner to provide the propulsive force to move the cleaner in a random manner across the surface to be cleaned.
In U.S. Pat. No. 3,803,658 to Raubenheimer discloses a cleaning device which employs a water cut-off valve carried in rotational movement by a wheel driven by the flow of liquid through the cleaner. As is typical for a suction cleaner, a flexible hose leads from the suction chamber of the device to the suction side of the filtration system pump. When in use for cleaning a swimming pool, the hose becomes filled with water and the continuous opening and closing of the valve causes the hose to jerk. As the suction against the surface to be cleaned is momentarily released each time the gate closes, the jerking movement of the hose causes the head to move over the surface.
A water interruption pool cleaner developed by Chauvier and described in U.S. Pat. No. 4,023,227 uses the oscillatory movement of a flapper valve of substantially triangular cross-section displaceably located in the operating head of the cleaner and between two valve seats to alternately close off the flow of water drawn through a pair of passages in the cleaner which is connected by means of a suction pipe to the filtration system pump. The passages are located parallel to each other and are preferably oriented at an angle of 45xc2x0 from the surface to be cleaned. The sudden halt of the flow of liquid through one passage applies an impulsive force to the apparatus due to the kinetic energy of the fluid flowing in the passage. This impulsive force is sufficient to displace the pool cleaner along the surface to be cleaned. Further, due to the inertia of the liquid in the passage to which flow is transferred, the pressure differential between the low pressure in the head and the ambient pressure of the water surrounding the cleaner is temporarily reduced, thereby decreasing the frictional engagement between the head of the pool cleaner and the surface, allowing the cleaner to be displaced.
By way of further example, water interruption pool cleaners which are more compact than the Chauvier device described above are disclosed in U.S. Pat. Nos. 4,133,068 and 4,208,752 issued to Hofmann. They employ an oscillatable valve adapted to alternately close a pair of passages in the head of the cleaner. A baffle plate is disposed in the head between the inlet and valve to cause one of the passages to be more restricted and less direct between inlet and outlet.
U.S. Pat. Nos. 4,682,833 and 4,742,593 to Stoltz and Kallenbach respectively, achieve autonomous water interruption by providing an assembly including a tubular flow passage at least partly defined by a transversely contractible and expandable tubular diaphragm, the tubular flow passage and tubular diaphragm are enclosed within a chamber formed by the body of the cleaner. The assembly includes means whereby pressures internally of the tubular diaphragm member and externally of tubular diaphragm member within the chamber formed around the member by the body are controlled so that, in use with fluid flowing through the diaphragm, it will be caused to automatically and repeatedly contract and expand. A pulsating flow of fluid through the assembly results and in forces cause the displacement of the pool cleaner apparatus over a surface to be cleaned.
To effect interruption of an induced flow through a swimming pool cleaner, U.S. Pat. No. 4,807,318 to Kallenbach discloses a tubular axially resilient diaphragm located within a chamber. One end of the diaphragm is closed and adapted to hold normally closed a rigid passage from the head of the pool cleaner to the usual form of suction pipe which connects the pool cleaner to the filtration unit. The diaphragm and its closed end also provide means for subjecting the interior of the diaphragm to variations in the pressure of water flow through the cleaner during use.
U.S. Pat. No. 4,769,867 to Stoltz describes a water interruption pool cleaner having a passage there through from an inlet end to an outlet in communication with a suction source. A valve in the form of jaw-like members is located at the fluid intake end of a rigid tubular section within a passage of the cleaner. In response to an induced flow of water through the valve and the tubular section, the jaw-like members automatically move relative to each other about an axis transverse to the length of and adjacent the end of the tubular section. The members are tapered towards each other to an inlet between them at their free ends with flexible membranes located between the sides of the jaws.
In another pool cleaner invention described in U.S. Pat. No. 4,817,225 to Stoltz, water interruption is achieved by means of a spherical closure member which is free to move in the head of the cleaner towards and away from a closure valve seat located at the upstream end of the outlet from the head. A hollow axially contractible resilient member is connected to the outlet at one end with its other end is connected to a flexible suction pipe.
U.S. Pat. No. 5,404,607 to Sebor for a Self Propelled Submersible Suction Cleaner uses an oscillator pivotally mounted within the flow path of a suction chamber to cause abrupt changes in water flow and thereby impart vibratory motion to the housing. Shoe means incorporating angled tread elements cooperate to move the housing along a forwardly direction of travel in response to the vibratory motion. Means are provided for converting a reciprocal angular movement or to and fro movement of the oscillator to an angular movement in one direction for purposes of driving a shaft.
To enable the Sebor ""607 cleaner to turn at established intervals throughout its travel over the surface to be cleaned, a drive gear is affixed to the shaft and engages a gear train which, in turn, engages a rotatable coupling at defined intervals to generate rotation of the coupling at these defined intervals. When in use, the rotatable coupling is connected to a flexible suction hose in communication with a filtration system pump.
Typically, a flapper valve used in such devices emit a hammering sound which can be irritating to a user. By way of example, if the swimming pool is located close to a building, the sound may resonate through the structure and be audible inside the rooms. Many devices known in the art are large and cumbersome. This impairs its maneuverability and effectiveness in smaller-sized pools and those where the transitions between the walls and/or between the floor and walls are sharp or tight. Debris such as twigs, berries and stones may become trapped in the operating head between the flapper valve and the valve seats. In order to clear debris or perform other maintenance tasks, it is difficult to gain access to the valve chamber, the flapper valve, valve seats and the openings in communication with the passages.
Sticks and larger pieces of debris may damage or puncture the flexible tubular member or may become entrapped in the members. Access to and removal of the flexible tubular member which is enclosed within a chamber is difficult and typically a non-technical person will avoid attempting easy repair. Replacement of the member may require tools which a typical homeowner may not have or be comfortable using. Often times, the pool cleaner provides a strong suction for effectively moving over the surface to be cleaned, but to its detriment fails to create a suction flow through the cleaner sufficient to remove sand located on the surface to be cleaned.
In view of the foregoing background, it is therefore an object of the present invention to provide a device for cleaning submerged surfaces such as those found in swimming pools. In particular, it is intended that the device is minimally intrusive with regard to both noise and overall size, is functionally and mechanically simple, is easy to install, is less prone to entrap debris than existing devices, incorporates easy access to the suction chamber for the removal of entrapped debris and includes means for maneuvering away from obstacles. Yet another object of the invention is to provide steering for directing the cleaning device on the submerged surface to maneuver away from obstacles. Further objects and advantages of the invention will become more apparent from a reading of the following description of the invention and embodiments thereof. It is also contemplated that the system and method are useful in fluid environments other than swimming pools and spas.
According to the invention, there is provided a device for cleaning surfaces submerged in a liquid. The device includes a housing in communication with a suction pump and motor by means of a flexible elongated hose connected to a coupling located at an exit end of the device. The coupling is rotatable in a preferred embodiment. The cleaning device incorporates at least one suction chamber or flow passage comprising an entrance end in proximity to the submerged surface to be cleaned and an exit end communicating with the coupling. The axis of a passage through the chamber is angled in a forward direction of travel with respect to the surface to be cleaned. A flow control valve is provided within the chamber or flow passage to cause, upon application of suction flow through the chamber, an automatic, repetitive interruption of the fluid flow therethrough, and thereby resultant forces capable of propelling the cleaner forward in the general direction indicated by the exit end of the chamber and the hose coupling.
The suction chamber comprises at least two sides, a front wall and a rear wall. The front wall is generally lateral to the direction of travel of the cleaner. To provide access to the inside of the chamber and the flow control valve, at least a portion of a wall or a side is detachable from the remainder of the chamber.
The flow control valve comprises at least one flap member mounted within at least one suction chamber. The flap member comprises two ends, two sides, a front face, a rear face, and at least one substantially rigid portion engaging the flexible portion. In a preferred embodiment, the flexible portion comprises resilient rubber-like material. Alternately, the flexible portion comprises multiple components or materials (including non-resilient materials) in a cooperative arrangement designed to perform the function of the flexible portion. Each end of the flap member is mounted between two sides of a suction chamber about axes generally transverse to the flow of liquid through the chamber. The flap member and the chamber in which it is mounted are dimensioned such that at least two sides of the flap member remain in close communication with at least two sides of the chamber. A substantially rigid portion of the flap member is pivotally mounted closer to the exit end of the chamber and away from both the front and rear walls. A flexible portion of the flap member is mounted closer to the chamber entrance end and attached to or in close proximity to the rear wall of the suction chamber. At least a portion of the flap member must be capable of travel into a position of close proximity or contact with the front wall of the chamber to thereby substantially close the passage through the chamber between the front wall of the chamber and the front face of the flap member. The dimensions of the chamber and the rigid and flexible portions of the flap member as well as the positions in which the flap member portions are attached within the suction chamber, will in combination determine the rate and intensity of interruption of fluid flow through the chamber.
When the suction pump is activated, it causes a flow of fluid through the chamber and primarily through a first passage between the front face of the flap member and the front wall of the chamber. The flow through this passage will cause the flap member to be drawn to a position in close proximity or contact with the front wall of the chamber. This action will substantially close the first passage, substantially interrupt the flow of fluid through the first passage, and cause a quantity of water to impact a front face of the flexible portion of the flap member. Restricted flow of fluid will occur between a side of the flexible portion and a wall of the chamber and then via a second passageway between a rear face of the flap member and a rear wall of the chamber. In this manner, the flexible portion acts as a baffle to water flow through the second passageway. Simultaneous with the interruption of fluid flow, the action of the pump will cause a lower fluid pressure zone in the suction hose and in the volume of the chamber downstream of a flexible portion of the flap member. The impact of fluid on the front face of a flexible portion and the lower pressure impinging upon the rear face of a flexible portion of the flap member each cause the flexible portion to deflect towards the lower pressure zone. This action upon and of the flexible portion will apply leverage to the rigid portion and cause the rigid portion and remainder of the flap member to pivot away from the front wall of the chamber, thereby reopening the passage for fluid to be drawn through the chamber. This sequence of events is repeated for as long as the pump is in operation, and causes an automatic reciprocating movement of the rigid portion of the flap member and a regular interruption in fluid flow through the suction chamber for providing a forward movement of the pool cleaner along the surface to be cleaned.
In a preferred embodiment, the flexible portion comprises two lengths of resilient rubber-like material separately mounted closer to the chamber entrance end and attached to or in close proximity to the rear wall of the suction chamber. This arrangement provides a volume between the two flexible portions and the walls of the chamber. The sides of the flexible portions are in close proximity with at least two walls of the chamber thereby enabling the flexible portions to perform as baffles and restrict the flow of water from said volume and the flow passage through the chamber. At least one aperture in a section of the wall of the chamber may be provided to allow, when the cleaner is submerged in a liquid, communication between water contained in said volume and water outside of the chamber. During operation of the device, this arrangement provides a buffer zone of relatively higher pressure impinging on one face of each length of flexible portion, the other face of each such flexible portion being in contact with water at a lower pressure as it is drawn through the chamber towards the hose and suction pump. This arrangement significantly diminishes the propensity of water-borne debris to become lodged between a side of a flexible portion of the flap member and a wall of the chamber which would impair operation of the flap valve.
Sealing means is attached to the rigid portion of the flap member to minimize the flow of water between the sides of a rigid portion and the walls of the suction chamber. The head of the cleaner is connected to surface engaging means such as a detachable shoe suitable for engaging the surface to be cleaned and for supporting the head. To improve the ability of the cleaner to orient the surface engaging means against the surface to be cleaned, floats and weights are attached to parts of the cleaner. To improve the suction grip of the cleaner to the surface to be cleaned, a flexible sealing flange is detachably connected to the shoe. In a preferred embodiment, at least one aperture is provided in the sealing flange such that water and debris may be drawn through the aperture from the upper surface of the sealing flange and then into the entrance end of the suction chamber proximate the surface to be cleaned.
To enable the cleaner to maneuver away from obstacles, the cleaning head may be rotatably attached to the ground engaging means. Automatic means are provided to continuously or intermittently positively rotate at least a portion of the body of a swimming pool cleaner in at least one direction relative to the surface engaging means of the cleaner. Yet further, means are provided to automatically rotate the body of a swimming pool cleaner in a first direction and then another direction relative to the surface engaging means of the cleaner.
To assist the steering, improve maneuverability of the cleaner and help avoid the establishment of repetitive courses across the surface to be cleaned, the sealing flange includes at least one out of round side and/or finger and/or stiffening means suitable for engaging a swimming pool wall or obstacle while the surface engaging means are engaged with the floor of the swimming pool.